Why climb for ice?

Discussion in 'Cleared for the Approach' started by SkyHog, Apr 18, 2005.

  1. sba55

    sba55 En-Route

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    Interesting stuff, Dave. I completely agree with you on the dangers of icing, just found it interesting that you saw such a significant loss of speed. Like you said, maybe there's something going on besides the prop.

    -Felix
     
  2. kgruber

    kgruber En-Route

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    My old F-86 buddy said icing was never a problem. Just speed up to 350 and it never forms.
     
  3. sba55

    sba55 En-Route

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    Makes sense, Scott. As a general rule of thumb, I don't depart in the winter if I can't get to the MEAs without being in IMC below 0. In this area, that's usually possible because it's rare to have really low ceilings once you get away from the Bay.

    Well, I finally have a very accurate temperature probe that is located on top of the aircraft (next to the GPS antennas), so at least I won't be collecting ice with the OAT showing as 38 ;)

    -Felix
     
  4. sba55

    sba55 En-Route

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    Interesting, I didn't know that. Is there a way to know if this particular probe would be affected? It does have a tiny vent hole, but nothing else. There's quite a lot of electronics in there, so I suspect that it would be waterproof...
     
  5. gismo

    gismo Touchdown! Greaser!

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    Ice definitely slows a Baron most of the time. I regularly see a 10-20 Kt loss just from the buildup on unprotected surfaces and it doesn't take 2+ inches to do that.
     
  6. bbchien

    bbchien Touchdown! Greaser!

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    Everyone here know which way to push the yoke to recover from a tailplane stall?
     
  7. SkyHog

    SkyHog Touchdown! Greaser!

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    Trick question, I presume?

    You wouldn't push the yoke at all, would ya? Tailplane stall would be broken by increasing angle of attack, right?
     
  8. bbchien

    bbchien Touchdown! Greaser!

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    No, straight up question. NOT of the "stump the chump" variety. Survival knowledge, like recovering from a spin.

    Yoke forward. Think UpsideDown airfoil, Nick.

    If it remains stalled, you're a lawn dart.

    Go to negative AOA to get it unstalled. It's just as counterintuitive as lowering the nose to glide farther- "stretch the glide".

    Revision 9/12/08: I think Lance is correct, see his URL. Pilots are NOT trained to recognize/recover from this. The data are double counter-intuitive.
     
    Last edited: Sep 12, 2008
  9. SkyHog

    SkyHog Touchdown! Greaser!

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    Then its no different from a normal stall then, is it? Push the yoke to recover from any stall?
     
  10. Henning

    Henning Ejection Handle Pulled

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    Depends on which way the tail was pushing when it stalled. Typically it happens on short and is an unrecoverable situation. That's why you keep the throttles hammered till the wheels hit. Better to run out of runway at 45kts than lift at 95kts and 200ft.
     
  11. tonycondon

    tonycondon Gastons CRO (Chief Dinner Reservation Officer)

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    ive also noticed a pretty immediate speed drop in the 421 when you start to pick up ice. 5-10 knot loss right away once it starts to build.
     
  12. gismo

    gismo Touchdown! Greaser!

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    I think Bruce is wrong about this. According to NASA the proper techniques are pull back on the yoke/stick, reduce flap extension, and in many cases reduce power somewhat.

    A related question is what are the symptoms of an incipient tailplane stall and how would you distinguish between a tail stall and a wing stall especially when ice is present?
     
  13. gismo

    gismo Touchdown! Greaser!

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    A tail stall is more likely with higher power/speed. Trouble is, the higher speed (and power) is needed in ice to prevent a wing stall. Talk about a rock and an unsoft location.
     
  14. flyingcheesehead

    flyingcheesehead Touchdown! Greaser!

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    I hate to sound like a two-year-old, but...

    Why? And why?
     
  15. gismo

    gismo Touchdown! Greaser!

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    NASA Lewis did some research on this. Their study generated the recommendations I posted. You can view a video on the study at:

    http://tinyurl.com/4omfck

    The issue is airflow separation and/or reversal underneath the tailplane. Adding flaps increases the AOA on the tail because of the resulting additional downward deflection of the airflow behind the wing. Pulling back on the yoke/stick increases the camber of the tail airfoil and that should increase the downward lift
    of the tail.
     
  16. bbchien

    bbchien Touchdown! Greaser!

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    Lance, you're right. There are two graphics back to back in the Jepp Ice section (CFI renewal) and they don't ask about tailpane recovery in the chapter exam (in which I got 90%). Their text actually agrees with the NASA Lewis lecture. The photo with the big arrow, that I remember, is designed to illustrate yoke lightening.

    I'm still a little unsure how steepinging the AOA by pulling back on a stalled surface is going to recover it, but the NASA lewis url make it clear that if you let airspeedget too high you also exacerbate the condition.

    Ive attached the graphics, which I need to remove in a day or two.
    I'm correcting (adding) to my previous post.

    You would think that a yoke push would decrease AOA and unstall the tail, but apparently the thing behaves like a deflection board at that point, with all the tufts demonstrating un-attached airflow. Sigh.

    Gotta go check my tail boots.
     

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    Last edited: Sep 12, 2008
  17. Dave Siciliano

    Dave Siciliano Final Approach

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    Well: we checked our systems pretty thoroughly. Prop heat worked on each prop. Pitot, fuel vent and stall heat worked. We never lost MP, RPM or FF, so, we were making designated power. It the induction air inlet had iced, we would have seen a change there. It wasn't static as the IAS dropped, so did the gps ground speed. We did see some pretty nasty rime on the intake to the intercooler. No ice slinging off prop and pretty light when we popped the boots, but, with all systems working, it seems it was ice accumulation on the non-k-ice surfaces.

    I agree with Lance, we usually see maybe 10 knots slower as we accumulate ice on the AF, but this slowed faster than normal and slowed us more than normal. Of course, there are different kinds of ice.

    This just surprised us because of the lack of visible accumulation. I've carried a lot more on the plane that I could see without this degradation in airspeed. Just makes the point, don't stick around in icing conditions any longer than necessary. From what you can see, you may think you're fine; degradation can occur pretty quickly.

    Best,

    Dave
     
  18. skyflyer8

    skyflyer8 Line Up and Wait

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    OK, so I was going to re-read this thread for my education, but post #1 is "..." now? :dunno:
     
  19. flyingcheesehead

    flyingcheesehead Touchdown! Greaser!

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    Just further proof that on the Internet, pilots don't even need a question to come up with a zillion different answers. :smilewinkgrin: :rofl:
     
  20. SkyHog

    SkyHog Touchdown! Greaser!

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    I don't see dots, I see the original question....
     
  21. sba55

    sba55 En-Route

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    Yes, _now_ I see the original question, too. The power of the edit button ;)
     
  22. j1b3h0

    j1b3h0 Line Up and Wait

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    In 23,000 flight hours, I can count all the times I've had bad ice on one hand.

    What I've learned: Boots on a piston powered light airplane are a little bit like leathers while riding a motorcycle - they make you feel good, but if you get in any real ice - or fall off the bike, you're still in trouble. I'd rather be flying a turbocharged single without deice equipment than a non turboed twin with boots, hot props, etc.
    Airplanes with thick airfoils can collect a lot of ice and still fly okay, but with any piston airplane, if you get any appreciable ice, you're out of business.
    Turboprops are often operated in and out of icing conditions (and well equipt to handle them). Not only equipt with boots, etc, but with horsepower. When picking up ice in a turboprop, I keep the nose down and the indicated speed way up - I want whatever ice I do get to be on the wing leading edges and the raydome - so I can shed it with the boots. Don't want any ice on the belly. If one gets to the mid-teens in the climb and the airplane slows down and gets ice on other than the leading edges/protected areas, you'll never reach the twenties.
    Worst ice I ever had was while flying a Saab 340 from San luis Obispo to LAX at 11,000ft. Had only leveled off for 10 minutes or so before we had enough ice for the happy hour. Props were slinging large chunks into the fuselage, the whole front of the aircraft was covered by 1 inch plus of rime, our indicated airspeed was reduces by 35kts, even with climb power. Had to turn toward the ocean and descent several thousand feet to get rid of it.
    Freezing rain is a different kettle of fish: almost any airplane can be rendered unflyable in a matter of minutes with the type of rapid accretion FR can make. Stay away.
    Whatever airplane you fly, you'll find that there's a certain temp range in which the airframe will acrue ice, usually only a 10 dgree spread or so. Avoid those temps in visable moisture.
     
  23. poadeleted20

    poadeleted20 Deleted

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    In 42 years of flying, I've lost count of my icing encounters, and I've yet to have good ice.
     
  24. Let'sgoflying!

    Let'sgoflying! Touchdown! Greaser!

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    Always great to hear some real world experience on icing, thanks for checking in, Doug.
     
  25. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    While I understand your point, I believe that Doug's is relevant.

    The worst ice I've encountered was still very manageable with the equipment I had. So I managed and took the appropriate course of action for getting out of there. I also knew taking off what I expected to encounter.

    Good reminder, folks - ice season is starting.
     
  26. Aztec Driver

    Aztec Driver Cleared for Takeoff

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    Ran into some ice heading to BUF the other day. All forecasts seemed to indicate that 8000 would be above it. climbed up through the clag and started picking up a little light rime in the climb, leveled off at 8000 and could see that another 500 feet or so would get above it. Started to collect both clear and mixed ice on level out. Even started to run beyond the scope of the boots. climbed up to 10000 in the clear.

    Came back at 9000 and, by that time the clouds were at that level, too. Started picking up another miserable load of ice, again both clear and rime, and again, running back beyond the boots. Had to descend to 5000 to shed the ice.
     
  27. Richard

    Richard Final Approach

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    I always saw this thread as how a pilot dealt with an icing encounter. So please explain what was your "appropriate course of action".

    And since you mention you knew what to expect before departing, did your course of action differ from your plan formulated prior to departing?
     
  28. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    Good point.

    The goal of dealing with an icing encounter successfully is figuring out how to get out of it. This ends up meaning one of several options:

    1) Climb (get above it)
    2) Descend (get below it)
    3) Truck ahead (get out of it)
    4) Divert to another airport and land

    Which one I have chosen has depended on the situation. Ideally, I'll get on top of an icing layer, fly over it, and descend either through it or past it.

    Sometimes, trucking ahead ends up being the best option. If you pick your altitude properly, then a different altitude may only get you more ice. Climbing brings with it the problem of ice on the underside of the wings, which your boots will not help you with. Climbing through ice in the Aztec, for instance, can result in a plane with a load of ice under the wings that doesn't like to fly very well, and also doesn't want to climb very well. However, it can load up a boatload of ice on the leading edge of the wings, ugly ice, and still be happily putting along.

    Another thing that can be important is finding a layer of no ice when you're surrounded by ice. I've had times when everyone above me and below me is iced up, but I'm not getting any. Careful weather analysis helped me pick the altitude to fly at, and it worked.

    No, but that's because the course of action I've planned ahead has always worked, and sometimes the course of action planned has had several "if-then" clauses. One day, the forecasts will not represent the actual weather well enough, or I'll have a bad plan. And then I'll need to differ in my course of action.
     
    j1b3h0 likes this.
  29. bbchien

    bbchien Touchdown! Greaser!

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    You climb for ice if the SkewT-Log P (issued 3 hours ahead) predicts a warm nose above.

    If you didn't study the SkewT-Log P, and you are flying a piston aircraft, FIKI or not.....well you get what the goddess of weather dishes out and Lord Help You.
     
    Last edited: Oct 23, 2011
  30. poadeleted20

    poadeleted20 Deleted

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    The problem is folks who believe ice is manageable without that equipment, or that having deicing equipment makes all ice manageable, and suggesting that one can fly 23,000 hours and only find "bad ice" a handful of times scares me. To my thinking, all ice is bad ice. The only differentiation is that some ice is worse.
     
  31. j1b3h0

    j1b3h0 Line Up and Wait

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    Sir - When I say really bad ice, I mean ice that made me have completely regroup not just climb or descend a little to get out of it. Sometimes I get ice every day, just part of the job. Same job (many different airplanes) for almost 25 years. A trace of rime is no reason to hit the silk, and neither is it to be just ignored without efforts to get clear of it.
     
  32. poadeleted20

    poadeleted20 Deleted

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    I think perhaps we're in violent agreement.
     
  33. j1b3h0

    j1b3h0 Line Up and Wait

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    It's better to fight a 60kt headwind than a 50kt headwind and a bunch of ice, too.
     
  34. Let'sgoflying!

    Let'sgoflying! Touchdown! Greaser!

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    I enjoyed reviewing this thread (thanks to Nick). Timely.
    If we ever get any moisture down here!
     
  35. Rex Kramer

    Rex Kramer Pre-takeoff checklist

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    Worst icing I've seen is at the top of cloud layers...


    There be dragons..
     
  36. BellyUpFish

    BellyUpFish Cleared for Takeoff

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    Worst ice I've ever seen was at 11,000 in a ragged top. We had the heat on high and it was still accumulating.

    [​IMG]

    [​IMG]
     
  37. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    Correct. The big thing I always convey to my students is if you don't have the equipment, you simply don't play. If you do have the equipment, then your go/no-go just got harder. The Skew-Ts are step 1.

    I think the difference is one of semantics. I tend to agree with Doug's semantics, but yours is what I'd use in conveying the importance of treating ice with respect to someone unfamiliar.

    Also true, covered under 4), because "another airport" could be "back home."
     
  38. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    Hence why you can sometimes find an altitude within a cloud that has icing. I've had people getting iced up above and below me, while not picking up any myself.
     
  39. Jaybird180

    Jaybird180 Final Approach

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    one would think that in the course of only 6 years the characteristics of airframe icing would be stable enough to elicit a consistent ideology and communicate that to the frigid zone virgin such as myself.
     
  40. Jaybird180

    Jaybird180 Final Approach

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    Having so made this pronouncement, I hereby swear off PoA due to the inability of anyone on this site to have a consistent sentiment or erudition regarding such matters of critical importance.


    Okay, I'm joking
    Seriously, To summarize, I read that ice will only form when temps reach -2C, EXCEPT in cases where Scott said it can form at 15C.
    Am I kunfuzed yet?